How many times can I take metformin per day?

Yes, you can take metformin with Glyburide. They have different modes of action and can work together to control blood glucose.

The dosage is:

Usual Adult Dose for Diabetes Mellitus Type II

500 mg orally twice a day (with the morning and evening meal). Some patients may need to take it 3 times a day with breakfast, lunch and dinner.

Extended Release:
500 to 2000 mg orally once a day (with the evening meal). Maximum daily dose is 2500 mg.

https://www.drugs.com/dosage/metformin.html